Torque wrench



K R LARSON TORQUE WRENCH Filed Jan. 14, 1941 2 Sheets-Sheet l Feb. 23, 1943.

K. R. LARSON TORQUE WRENCH Filed Jan. 14,

2 Sheets-Sheet 2 INVENTOR. .K NNETH R.LA so/v.

I! l I ATTORNEY.

turning operation. I 4 o 3 One object of the present invention is to sun plify the construction and improve the operation Patented Feb. 23, 1943 UNITEDTY TAT Snap-On 1s .coi'poratiem 4 corporation of Wigwam v H Application January14, 194 1, V n w .l-}1 .Ji This invention relates to tur'ning devices'faiid' more particularly to torque measuring wrenches,

although certain features thereof'may beamployed with equal advantage for other purposes. i

It contemplates more especially the provision of a simple, dependable, accurate and compact torque measuring wrench that accurately 'desig' similar nates the force applied in nut turning and movements under all conditions Most torque wrenches measure the iiex'fim aj beam which resists the turning force of a w'renqh in order to measure the amount of torque or force applied in nut turning and similar operations.- Then, too, the amount of torque has been'measured by determining the degree of twist in a shank or shaft. While some torque wrenches have em bodied this principle, there has been no apprecia-* ble effort made to adapt such to "commercialwrench structures of the conventional handleor lever arm type. The desirability of utilizing/the degree of twist in the shank or shaft as the measuring expedient in nut turning and similar operations, has not been resortedto with the utmost advantage from the'standpoint of translating the degree of twist to an indicator at a pointer maximum displacement so that accurate measure- Wis type'that'is accurat mat-mastitisspams.

still anothe'r' object is to provide 'agtorque meas uring turning tool having improved torsion: trans-.1 lating 'rnea'ns associated therewith for measuring the torqueapplied in'the turning-operation;

with 'a'fshank subjected-*tio twistier: operating:

measuring instrumentalities with% is. translated twist; effect for accuracy.and.dependability;.

still furtherobject ,isiftotriprovide aiitorque:

- wrench with a turning shank. having alcompara tively long indicating rod-extending therefrom for operativeconnection to measuring instrumental-n ti es'at 'a= point'of-accen tuated displacementu Still a-iurth'efirobjet iStOSpIOVidGHSI WIBHCh havinga rigid casing element foriattachment ofa turning shank subjected'toturning movement to provide a calibrated twist thereinthroughuthe medium of alight, flexible, and-elongated rod connected to'measurin'g instrumentalitiesrat a point;

of "greatest displacement responsive to torsional-l shank stresses andstrains'lj.- .7 Other objects and advantages will appearjf-rom the following 'description 0f arr'r-il-lustrativeqeme; b'odiment oftheprsentairivention:

ments can be recorded byreducin'g the'error {ac-"- tor to a minimum.

The importance of accuracy in torque wrenches cannot be over-emphasized, and the degree of ac curacy depends largely upon theelimination or or substantial reduction in friction,"lagand fre'e play between relatively moving parts. important in torque wrenches thatembody'the principle of flexing -'a torque resisting" beam' to' provide the desired reading; how'even-b'etter re sults have been found possible in torsion typewrenches embodying" teachings of 'the present invention. In accordance with" the teachings of the present invention, 'the torsion measuring principle has been embodied in theco'nventiona'l" type lever-arm wrench with minimum friction,"

lag, free-play, and maximum translation of th'erelative twist of the load' carrying member.

Torque measurements are possible, there-fore-,-witha negligible error factor and nut turning operations are accurately measured under all conditions and capacities irrespective of the position of applied force along the lever-arm' for eifecting the of devices of the character mentioned.

Another object is to provide a'snjnpiema com;

pact torque measuring wrench of thelever-arm Figure 1 is a plan viewot anwrencli vembocb'ingu features of thepresenliinven'tiom': I

Figure" 2 a: sider vie'w sin: elevatio wrench-shown in- Figure 1." tie: Figure3 is a-bottom plan view-oi-the'wrench shown in Figure 1, part of the handle beingbroken awayio'rconvnience. Figure :4 is a sectional .viewltak'en substane; tiallyalongline IV-'-'IV.- or Figure-1. Figure 5 is a sectional-view taken substantially a1ong 1ine' V Vof Figural." Figure 61s a sectional view :taken' substantially, along1line'VI VI of Figure .311

Figure 71s a plan' viewo of an"underside eta casing-cover platerand its assembled-instrumentalities.-"'

Figure 8 is a sectional view taken-substantially along" line. VIIIa-VIII 'of- Figure '3. i

-Fi'gure 9lisv'a topwiiexiikof thefwrenc'h shown in Figure 8 with the easing. covenplateremoved to i illustrate the inner shape: thereof.-&:--' -Figure- 1014s. a arrag'mentary sectional-view taken substantially "alongt-line "Xi-5x, of Figure .8...

Figure 11 is a"perspectlve-viewiota torsional turning shank element, before being applied to therig'id casing cover'plate:;1- i=3; f Figure 12:- i's' a-.:Iragmentary" sectionalgview taken substantially 'along line i-XII-reXLI of, Figure 8. i

- 'Ihe'structure selected for illustration comprises a solid handle member ll of standard construction having an elongated chambered wrench shank or body Ii cast or otherwise shaped to present inclined side walls I2 and I3 terminating in a semi-circular top or head extremity II. The handle i with its chambered body ll is preferably though not essentiallycast from an aluminum alloy so as to possess the desired strength and lightness for convenience and manipulation in nut turning as will appear more fully hereinafter. It will be observed that-the handle shank or body ll consists of the inclined side walls i2-l 2 which converge inthe direction of the handle I0 and also toward the bottom wall l formed integral therewith to deflne an elon- 1 Its'hould be noted gated chamberedinterior ii. that, in this instance, the side walls l2-il not only converge toward the handle l0 (Figures 1 and 9) but alsotoward thexbottom l5 (Figures 3 and 9), to define a compactand well balanced casing orbody II. 1

a The body-or casing shank H is,-in- 'this ,instance-covered by a rigid steel plate I] that is shaped to conform with the configuration of theb peripherally flanged openside ll opposite the. bottom wall I! to confront therewith and serve as a complement thereof. The lower or handle extremity I! .of the chamber I8 is of'the same general size and semi-circular configuration as the head extremity I it. The peripherally flanged II or the casing shank II for projecting through the circular recess 29 provided in the head II.

,A spring impelled detent '22 of standard construction is provided in a faceof the polygonal shank 22 for cooperation with a correspondingly sized and shaped recess provided in a wrench: socket or other turning implement that is teleaccidental detachment."

Wrench sockets or other turning implements (not shown) would normally be provided with a recessed, shank shaped and sized to conform with the polygonal extremity 32 of the revolublescoped (thereon for retentionthereonljagainst turning member' 2' so that the friction exerted, by thespiing impelled detent 22 would be effective in retaining the turning implement thereon against accidentalremova'l. As shown, the revoluble member bass cylindrical extension 24 constituting a turning shank which, in this instance. is formeduintegral with the annular shoulder II and polygonal shank 32in axial {913% tion therewith, The cylindrical turninggshank 24 terminates inan enlarged polygonal-tshoulopen edge ll of the casing ll extends around the I side walls l2--lvl'andtheir semi-circular head and handle extremities II and 19. The rigid face or cover plate 11 is shaped tocorrespond with-the'flanged openedge "including its 11p creasing body I i and'semi-circular ends i4-,l 0,

thereby enclosing the chamber it and confining the torsion displacing, indicating. and measuring instrumentalities to be; described hereinafter. It will be noted that the handle shank-or. cas-,

ing body I l and especiallythe inclined side walls l2-l2 are reinforced'in the region of the threaded bores 22 byincreasing'theythickness of the cast peripheral flanse llas at 22-24, 25-46,

and 21-" so that the comparatively rigid and loadcarrying cover plate II can be effectively attached to the casingnbody llv which is greatly,

strengthened and "reinforced therewith.

In fact, the casing ll does: not sustain any appreciable turning load and primarily serves to confine the measuringinstrumentalities as a pro- III to rest, in this instance. upon the exterior- 7 ll is exteriorly disposed adjacent the cover plate; i1 so that the polygonal shoulder I l registers with the correspondingly shaped aperture gm-o;

der 25 having, in thisinstance, opposing circul ar edges 3H1 interrupted ,by; straight parallel sides 28-.4! for registry with a correspondingly shaped aperture 40 providedin the-head.region of the cover plate [1. Obviously, the shoulder 2.54 may be of any polygonalshape depending upon the dictates of commerclalpractlce.

, I The polygonal shoulder. ll has an enlargedcircular, disc 4| formed integral therewithim axial relation to the revoiuble turning-member surface of the cover plate" l1 and to conform in,

size and -,circular-conflguration with a semi-cine cular head extremity d2 of the cover plate ll.- So that the revoluble turning member ll maybe attachedto the cover plate I] to constitute, a

fixed element thereof, the cover plate-ifliand the disc ll of the revolubl'eturning member Il are,

each, in this instance provided with anpair, of aligned apertures "and 44, respectively,

As shown, the 4 4 in the duo ll, are interiorly threaded asat ll (Figure :11) to -re ceive fasteners such as-threaded studs haying-- theirheads disposed on the underside of the plate 111 (Figure 7) Y The studs ill proiect through the, apertures 42 inthe cover plate. H;

and threadediy ,engagethe correspondhnly threaded-aperture 44 of the disc, 4|. The .disc

vided in the cover plateJfl'. With this arrangement, the turning member II projects through the chamber vIt creme shank ,l I. sotha't the polygonal extremity 22 will be exterioriy ascessiblebeyondthe casing bottom II for engage tection against foreign substancesand impacts. The-cover plate II is sumciently rigid toavoid 1 a flex, distortion or consequential variation under turning load; The semi-circular head II of thebody II is providedwith a circular recess 29,

corresponding substantially in curvature therewith andsized to receive arevoluble turning member. 2| of substantially corresponding size for free rotation therein. The revoluble turning member-ll hasan. annular shoulder 2| formed,

inthis instance, integral therewith immediately above a polygonal wrench socket receiving extremity 22 which terminates beyond the bottom ment and disengagementfwith turningmembers, such" as wrench sockets and the likes- Should commercialpracticeso dictate. the -polygonal shoulder 2| may be dispensed with andthe turm,

ing member ll attached to; the coverlplate-JI' against turning therewith by means of a l of fasteners Ill. 1

-It should benoted thatthe mitt-13 member, isrigidiy attached-to the cover-plate; II that is preferably of rigid andnon-yielding material such' as steeiwhile the body or casing shank ll may becast or otherwise shaped fromaluminum in that the revoluble turning ber 30 is mounted for movement relative thereto in sustaining theturning load. The casingli does not directly carry any appreciable load.

Turning movement is imparted to a fastener such as a threaded nut through a wrench socket attached to the polygonal shank 32 of the revoluble turning member 30, responsive to manually applying force or effort to the handle H1 in one direction or another.

In order to measure the extent to which any fastener such as a threaded nut is applied through the manipulation of the handle |0,.the extent of twist sustained by the cylindrical extension 34 of the revoluble turning member 30 is determined in that this will be uniform for any predetermined applied force and will vary proportionately to the turning load imparted through the handle I that is primarily sustained by the rigid cover plate II. It will be observed that owing to the polygonal shoulder 35 on the disc 4| of the revoluble member 30 and the attachment thereof to the cover plate through the medium of the fasteners 45, any turning movement applied to the handle It! will be transferred to the coverplate I! which, in turn, will rotarily displace therevoluble turning member 30 which carries a nut or other turning implement to the end that proportional twist is bore 53 of the rod 46 to enable longitudinal adimparted to the cylindrical extension 34 anchored to the cover plate I! at one extremity 4| and free to twist at the other extremity 32 responsive to carrying the turning load.

In order to measure the degree of twist or torsion imparted to the cylindrical extension 34 of the revoluble member responsive to any turning operation, an elongated cylindrical indicator displacing rod 46, is in this instance of uniform diameter, and projects radially in the annular shoulder 3| of the revoluble member 30 as at 41 for fixed engagement to constitute a single acting unit or member therewith. The elongated rod 46 projects longitudinally of the body or casing shankll for confinement therein. So that the casing shank together with its associated instrumentalities may be as compact as possible, the cylindrical indicator displacing rod 46 is preferably disposed at a slight angle betwen the extremities 48 and 49 thereof (Figure 8) to avoid contact with either the bottom I5 or cover plate l1 and free to circumferentially move or oscillate for a limited extent depending upon the degree of twist imparted to the revoluble member extension 34 or the torsion effect therein responsive to carrying the turning load and its polygonal shoulder 35.

The elongated indicator displacing rod 46 need only be heavy enough to overcome the friction in the measuring instrumentalities' and the load occasionedby their operation without causing any flex in the rod 46. 1 Its diametrical size, howjustment of the rod extension 5| relative to the indicator mechanism to be hereinafter described. The longitudinal adjustment of the rod extension 5| will vary the extent to whichthe dial mechanism is actuated or displaced responsive to a predetermined torsional stress imparted to the shank 34 of the work engaging member'33.

This enables also the replacement of the rod ex tension 5| should occasion demand or should such become impaired in any nut turning opera-v tion. It should be noted that the rod 46 together with its reduced extension 5| functions exactly the same even though these were turned or otherwise shaped to constitute an integral unit; however, such construction would be somewhat more expensive from a production standpoint than the co-axial connected rods 46- -5-| serving as an actuator for measuring instrumentalities when displaced by the twist imparted to the turning member shank 34. v

The reduced rod extension 5| has a right angularly offset extremity 56 which projectsv transversely within the casing body chamber I6 near ever, may be determined by other factors such as the elimination of backlash and conditions of abusein actual nut turning operations.

For that reason, the elongated rod 46 in actual practice may be'somewhat heavier than otherwise required merely to carry a comparatively negligible load of operating the measuring instrumentalities without any flex in the rod 46.

It may be more desirable from a manufacturing standpoint to terminate the elongated cylindrical rod 46 just short of a lower circular handle extremity 50 of the cover plate l1 and join therewith a rod extension 5| of comparatively smaller diameter. To this end, the rod extension 5| has its upper extremity 52 projecting within an axial bore 53 provided in the lower extremity of the rod 46. The upper extremity 52 of the rod extension 5| is frictionally engaged the bottom end thereof for registry in a longitudinally elongated slot 51 provided in a lever 58 that comprises a part of measuring and indi-f catin'g instrumentalities to be presently described. The lever 58 is secured atone extremity thereof to a stub shaft 59 that carries a gear sector 60.

The stub shaft 59 is journalled in a substantially T-shaped bracket 6| that is mounted by means of threaded studs 62, in this instance three, to a circular dial casing plate 63. ,4

The gear sector, 60 meshes withfaipinio n 64 mounted on a stud shaft 65 journalled between the substantially T-shaped bracket 6| and the dial casing plate 63. The pinion stud shaft 65 projects through the dial casing plate 63 to carry an indicator pointer 66 attached thereto to confront an offset surface of the dial plate 63. The dial casing plate 63 has a calibrated dial 61 attached thereto to designate in foot pounds the degree of twist or torsionaleffect exerted on the revoluble turning ext nut or other expedients by proper engaging at tachment with the polygonal shank 32 while the manual force is applied to the handle l0. It should be observed thatthe offset extremity 56 of the rod extension 5| will be displaced within in the bore 53 by means of a tapered tightening sion 34 in fastening a ing member 46 therebetween.

dial casing plate to constitute an exterior confining member for the pinion shaft 65, the

indicator pointer 66 and the calibrated dial 61. A suitable transparent dial cover 69 is secured to'the dial casing ring 68 to confine and serve as protection for the dial indicator and the calibrated dial 61. The starting position of the one indicator 66 may beset relative to a. pin

serving as a stop that is anchored in the dial casing plate 63 to proje'ctthrough the calibrated dial 8]. type and is preferably of a type in which the a dial may be rotated for setting.

retainer bracket 12 that is anchored at its ex tremity by means of threaded studs 13-" to the underside of the cover plate I! (Figure 7) to maintain the actuator rod 46 and its extension II in operating connection with the measuring instrumentalities. I

'flie measuring instrumentalities' which are assembled as a unit to the dial casing plate 63 are attached to the exterior surface of the lower circular extremity 50 of the cover plate i I which is provided, in this instance, with a pair of apertures Ii-1' for receiving threaded studs therethrough to engage correspondingly spaced and threaded-apertures (not shown) provided in the casing plate 63. Consequently, the measuring and indicator mechanism can be attached to the cover plate I! together with the revoluble member Ill and its torsion displacing rod 6-H. The cover plate I! together with these instrumentalities are, in turn, attached for confinement in the chamber [6 of the body or casing shank Ii by means of fasteners such as the threaded studs 20.

It should be observed that the lower end of the chamber it of the body casing II is outwardly flared to define a circularly flared configuration 11 to conform with the size and shape of the lower extremity SI of the cover plate il together with the dial casing plate 63 and its confronting ring il. It will be apparent from the foregoing arrangement of parts that a manual turning Y force applied to the handle III will impart a corresponding turning eifect'to the revoluble turningemember 30. This creates a slight twist in the turning member extension or shank 34 which can be measured with the advantage procured through the moment arm dial indicator displac- This turning operation is transmitted to a suitable fastener or tool or implement or fastener such as a threaded nut which requires a predetermined turning load in securing it to the desired degree of tightness for the suitable performance of its intended function. This turning movement and sustained turning load will create a fractional twist in the revoluble member shank or extension 34 between its annularv shoulder ii and the polygonalstationary shoulder 35. This fractional twist created by the torsional effect on the cylindrical extension 34, will be translated to the measuring instrumentalities culminating in The indicator as shown is of a known the rotary displacement of the pointer it relative to the calibrated dial 6! through the medium of the elongated rod MI. The degree of twist or torsional strain within the turning member shank 34 is measured at the extreme end of-the elongated rod 6-H whichis greatest displacement. at

As a result, the rod 'Sl will accentuate the twist created in the revoluble headextension 3 4 to effect its return to the indicator pointer to an extent proportional to the length of thecelongated rod 465l. The measurement of the twist imparted to the revoluble head extension 34 at a point of maximum displacement ofthe comparatively long twist-translating 'rod HI is an important factor'in producing accurate read-- ings. Then, too, the rod lt -5i need only be heavy enough to overcome the comparatively negligible force required to actuate themeasur ing instrumentalities so that comparativelylittle' With the arrangement of parts above described;

the rod 46-41 comprising a single or sectional member is of such flexibility as to, preclude injury to the dial mechanism in the event the handle II is abruptly released or the turning loadshould fall by virtue of a rupture in the nut or bolt or other lnstrumentality that is being tightened. The rather fiexiblerod li-Sl would absorb a,

substantial part of the shock without permitting such to damage the dial mechanism or anypart thereof under abnormalconditions of abrupt're lease. Then, too, the pointer 66 is frictionally mounted on the stud shaft for rotation relative to or therewith.

This enables resetting of the dial indicator pointer 66 relative to the pin III prior to applyinga wrench to an instrumentality that .is to'be turned therewith. Any abrupt release ofthe nut turning load even though the comparativelyflexible rod 6-H would beunable to absorb'the entire shock owing to back-lash, would result in the pointer 66 striking the pin II and allowing the pinion stud shaft iltoberotatively displaced relative to the pointer 06 'wlthout'injury thereto in the elongated dial actuator rod 46-h. Any back-lash occasioned by the abrupt accidental release of the turning load would ordinarily jar, impair and render. permanently defective the measuring instrumentalities. 1 This can be largely overcome by the actuator rod extension which is highly flexible, resilient and possessed of only sumcient rigidity to overcome the measuring instrumentalitles connected thereto. Consequently, the severe stress and strains resulting. from any back-lashaction. will a be absorbed for the most part by the connect the actuator rod extension SI and thus protect the measuring instrumentalities in any'type of beam device under such abnormal conditions of abusive operation. 'The steel spring wire it is sufficiently rigid to carry the comparatively small load involved in actuating the indicatorinstru mentalities without any flex therein and yetsufficiently resilient to absorb any shock created in the abnormal operation of the turning head or revoluble member 30.

Then, too, the torsional displacement in a torsion-type wrench embodying a comparatively short load turning shank 34, is comparatively small in that the degree of twisttherein'would the point of tits be a minute amount approximating five thou-- sandths of an inch under normal loads. Because the elongated rod l65'i;actuates 'the dial 'me'ch-' anism at its (rod 46-5!) point-of maximum displacement, this minute torsional displacementof the load carrying shank 34 isappreciably" translated and accentuated at the dial' "end'-'ofthe actuator rod 465l. Even though therewas' an abrupt release of load, therefore, the'back'-' lash in the aforesaid structure would be negligible" and the actuator rod 46-5l would not-be called upon to withstand any appreciable back lash shock which could,'however, be'abso'rbed by 'the' resilient actuator extension 5| which? is prefer ably constructed from small diameter spring steel:

wire. 7

With the arrangement of partsabovede scribed,'it will be apparent that a very simple,

inexpensive and highly accurate torque measur ing wrench has been provided wherein there are few moving parts and the friction thereof has been reduced to a minimum to preclude variable and inaccurate readings. These features cou pled with the fact that the torsional stress' created by the turning load is measured 'at' the point of maximum displacement of the elongate'df dial mechanism/actuator rod, eliminates or re-. duces to a negligible minimum any inaccuracies even at small loads. e

Various changes may be made in the embodiment of the invention herein specifically de-' scribed without departing from or sacrificing any of the" advantages of the invention or ahyl features thereof, and nothing herein' shall' be construed as limitations upon the invention, its concept or structural embodiment as to the whole or any part thereof except as defined in jthe ap-- pended claims. A Iclaim: 1. In a torque wrench. the combinationwith an elongated handle member, of a torsion-re sponsive work engaging head member flxedfto one extremity of said handle member and adapt-' ed to twist in response to torque/an elongated rod anchored only at one extremity to said head member and extending freely along said handle member without connecting'therewith nor sustaining the work resisting load of said head;

member, and calibrated indicating meansflxed proximate to the other extremity ofsaid elo'n gated handle member for operative connection to the other extremity of said elongated rod to measure the twist of said head member responsive to sustaining a turning load with a turning force applied to said handle member.

2. In a torque wrench, the combination with an elongated rigid handle memberi'of' a work engaging head member anchored to said handle member proximate to one extremitythereof, an

elongated rod anchored only at one extremityto mal thereto, a casing complemental to-said rigid handleme'mber, a-torqueresisting shank on said work engaging turning head member projecting through said casing, and an elongated rod radially' anchored to said' torque resisting shank at 'a--'point:'spaced from the lattersanchorage, to said rigid'handle member to freelyext'end, therealong without connecting therewith, and calibrated indicating means on said handle mem v ber positioned laterally of saidwork engaging 3 turning head 'nieinb'e'r'for operative connection to the free extremity of said elongated rod to measure the degree of twist in said torque'resist ng shank occasioned in sustaining turning loads im part'ed-by'said work engaging'memb'er.

4; In a torque wrench,- the combination with a handle member, of a work-engagingturning' head member anchored in one endof saidrigid handle member, a casing complemental to' saidrigid'handle member, a torque'resisting shank on said work engaging-turning h'eadmember projecting through said casing, said work en-' gaging turning head member extending normal to said handle-member'an'd casing, an-elongated 'rod' radially anchored only at one extremity to" said torque resisting shank at a point spacedfrom its anchorage tosa'id rigid handle mem ber for'free extension along said handle "member and easing without connecting' therewith,=a-

flexible shock resisting extension on said rod, and

' calibrated indicating means on saidhandle mem berpositioned laterally of said work engaging tuming head member for operative connection to the free extremity" "of "said: flexible extension to measure the degree of' twis't-in said torque 1 resisting shank occasioned in" sustaining turningloads imparted by said workiengaging member.-

- 5. In a torque wrench, thecombination with ahandle member including afca'sing, of a rigidcover plate attached to said handle member cas ing, a torsion resisting work engaginghead member projecting through the casing of said handle member and anchored at rig'ht angles to said rigid cover" plate, an elongated rod anchored at one: extremity thereof to extend normal to: said work engaging member at a pointspa'ced fromits anchorage to said rigid cover plate; said 'el'ona gated rod extending along said rigid coverplate for confinement by said casing without connect ing with said cover plate and casing, and torque indicating means'on said handle member p'ositioned. laterally of said a work 'engaging' turn'ing head member for operative connection to' thefree extremity of said rod which is displaced re sponsive to applying force to said rigid-cover;

, plate through said handle member.

said work engaging head-member" at a point *6. In a torque wrench, the combination with a handle member including a-casing, of a rigid cover plate attached to said handle 'membercas' ing, a torsion resisting workengaging head member projecting through the casing of saidhandle' member and anchored at right angles to saidrigid cover plate, an elongated rod anchored at one extremity thereof to extend normal to said work engaging member at a-point spaced from its anchorage to said rigid" cover plate, a compar'atively flexible shock absorbing extension on said rod, said elongated rod extending along said rigid cover plate'for confinement by said casingwithout connecting with said cover plateand casing, andtorque indicating means on said ha'n dle member positioned-laterally of said work en'-' gaging turning head member for operativecom' nectionto the free extremity'of 'saidflexible-rodextension which is displaced responsive to apply ing force to saidlrigid cover plate through said handle member. a I n 7. In a torque wrench, the combination with v a handle member including arigid non-yielding plate, of a torsion resisting work engaging turning head member anchored in said handle memberproximate to one end thereof, said work engaging ghead member having a uniform shank extending normal to said handle memberpan said handle member for operative connection tothe free extremity of said elongatedrod which is displaced responsive to app ying force to said handle member.

8. ha torquewrench, the combination with a, handle member including a rigid non-yielding plate, of a torsionresisting work engaging turning headmember anchored in said handle member proximate to one end thereof, said work engaging head member having a uniform shank extending normal to said handle member, an elongatedrod anchored at one extremity thereof to said head member shank at a point spaced from its anchorage to said handle member, said elongated rod extending longitudinally of said handle member, said elongated rod :terminating'in a free.

highly flexible extremity proximate to the end of .said handle member opposite toxsaid work chambered handle member to substantially the opposite end thereof, said elongated rodflterminating in a comparatively flexible shock absorb-a ing extension projecting. axially from the free extremity of said elongatedtrod, said flexible rod 1 extension having an oflset extremity, torque indicating means operatively connected to the 08- set extremity of said last named flexible extension which is displaced.responsive to'applying force to said handle member.

11'. In a torque wrench, the combination with a rigid handle member, of a torsion resisting work engaging turning head member having-.ia shank anchored to oneextremity thereof and projecting normal thereto for imparting turning movement to said .head member throughethe moment arm of said handlemember, an elongated rod anchoied to the shank of said head a member at a point spaced from said handle engaginghead member, and torque-indicating means on said handle member for operative connectionto the free flexible extremity of said elongated rod which is displaced responsive to apply! ing force to'said handle member. a

9. In a torque wrench, the combination with a handle member including a, g a Milie -Y d g, 'plate, ofa torsion resisting work engaging turning head member anchored in saidhandle mem ber proximateto oneend thereoLwsaidworkenjmember having auniform shank 1 extending normal to said handle member, an

- means, said'elongated rod means being suihcient- 1 ly rigid to actuatesaid torque indicating means and yet comparatively flexible to absorb the hock occasioned by abrupt load release inzsaid elongated rod;anchored at one extremity thereof I to "said headmember shank at a point spaced 1 from its anchorage to said handle membensaid elongated rod extending longitudinally of'said handle member, said elongated'rod terminating in a longitudinally adjustable and free highly flexible extremity proximate to the end of said handle member, and, torque indicating. means on said handle member for operative connection to the freeflexlble extremity of 'said elongated rod which is displaced responsive to applying force to said handle member, said elongated rod and flexible extremity being suillciently rigidto actuate said torque indicating means and millciently yielding to absorb back-lash occasioned by anfabrupt load release on saidwork engaging turning head member. e

, 10. In a torque wrench, the combination with achambered handle member, of a' torsion resisting work eng in turning head member pro-' lecting through said handle member proximate to one end thereoiqa rigid non-yielding cover 'plate for said chambered handle member, said resisting turning head memberanchored at right,

work engaging head member having a an-"-- chored'at right angles to 'saidrigid cover plate member anchorage point thereof, said elongated rod terminating in a free flexible extremity ad-- iacent said handle member proximategto' the otherextremity thereof, and torque indicating means on said last named extremity of said 'handlemember for operative connection to said flex-v ible extremity of, said elongated rod which is handle member.

-12. In a torque wrench, the combinationlwith a handlememberincluding a flat rigid plate, of a cylindrical torsion resisting turning head member anchored in said handle member plate to extend normal from one end. thereof, elongated rod means anchoredrat one extremity, thereof displaced responsive to applying force to said to said cylindrical head member at a pointspaced from said flat platesaid elongated rod means terminating in a free extremity proximate to'the other end oi said flat rigid plate, and torque indicating means onsaid handle member for connection to the free extremity ofsaid rod turning -head member.

43. In a torque wrench, the combination with" an elongated rigid'handle member, of a torque resisting turning head member anchored a'tlright angles proximate toone extremity of s'aidrlgidv handle member.-torque indicating means attached 7 to said handle membertproximate to the other,

extremity thereof, and means extending in spaced parallelism to said handle: member and normal v to said turning head member between said turning head member, and said torque indicating means tore'spond to the torsional stress in said turning head member responsive to sustaining a turning load, said parallel extendingmeans being I free to swing. from said 'head member to said indicating means without any mounting there-. between.

14. In a torque wrench, the combination with} an elongated rigid handle member, of a torque angles proximate to one extremity of said rum handle member, torque indicating vmeans. attached to said handle member proximate to the ,other extremity thereof, and an elongated rod extending inspaced parallelism to said handle member and normal to said turning head mem ber between said turning head member and said torque indicating means to measure the-torsional near one extremity thereof, an elongated rod anchored at one extremity thereof to saidhead member and extending normally thereto insaid stress in said turning head member responsive to sustaining a turning load, said elongated rod being suihciently rigid to actuate said indicatcluding a shank that resists rotation relative to said handle member to efiect a torsional stress therein responsive to sustaining a turning load,

torque indicating means attached to said'handie member proximate to the other extremity thereof, and means extending in spaced parallelism to said handle member and normal to said turning head member between said turning head member and said torque indicating means to respond to the torsional stress in said turning head member responsive to sustaining a turning load, said parallel 'extending means being free to swing from said head member to said indicating means without any mounting therebetween.

16. In a torque wrench, the combination with an elongated rigid handle member, of a torque resisting turning head member anchored at right angles proximate to one extremity of said rigid handle member, torque indicating means attached to said handle member proximate to the other extremity thereof, and an elongated rod extending in spaced parallelism-to said handle extremity to said handle member proximate to one end thereof and projecting normal thereto for imparting a turning movement therewith, the other extremity of said work engaging turning head member being adapted to engage work to impart turning movement thereto, an elongated torsion translating rod anchored at one extremity to said work engaging turning head member at a point spaced from said handle member anchor age point thereof, said elongated rod extendin substantially along said handle member, and torque indicating means attached to said handle member near the other end thereof for operative connection to' the other extremity of said elongated rod which is displaced without flexing responsive to applying force to said handle member to operate said indicating means. 19. In a torque wrench, the combination with 'a rigid handle member comprising a fiat rigid load bearing plate and a casing detachably connected therewith,- of a torque resisting work engaging turning head member anchored at one extremity to said handle member bearing plate and projecting normal through said handle member casing for imparting a turning movement therewith, the other extremity of said work engaging turning head member being adapted to member and normal to said turning head member between said turning head member and said torque indicating means to measure the torsional stress in said turning head member responsive to sustaining a turning load, said elongated rod being longitudinally adjustable to provide for variations in the calibration of the indicating means to insure accuracy.

17. In a torque wrench, the combination with a rigid handle member, of a torque resisting work engaging turning head member anchored at one extremity to said handle member and projecting normal thereto for imparting a turning movement therewith, the other extremity of said work engaging turning head member being adapted to engage work to impart turning movement thereto, an elongated torsion translating rod anchored only at one extremity to said work engaging turning head member at a point spaced from said handle member anchorage point thereof, said elongated rod extending substantially radially of mounting therebetween.

18. In a torque wrench, the combination with a rigid handle member, of a torque resisting work engaging turning head member anchored at one engage work to impart turning movement thereto, an elongated torsion translating rod anchored at one extremity to said work engaging turning head member at a point spaced from said handle member anchorage point thereof, said elongated rod extending substantially along said handle member, and torque indicating means attached to said handle member for operative connection to the other extremity of said elongated rod which, is displaced without flexing responsive to applying force to said handle member to operate said indicating means.

20. In a torque wrench, the combination with p a rigid handle member comprising a fiat rigid load bearing plate and a casing detachably connected therewith, of a torque resisting work engaging turning head member anchored at one extremity to said handle member bearing plate proximate to one end thereof and projecting normal through said handle member casing for imparting a, turning movement therewith, the other extremity of said work engaging turning head member being adapted to engage work to impart turning movement thereto, an elongated torsion translating rod anchored at one'extremityto said work engaging turning head member at a point spaced from said handle member anchorage point thereof, said elongated rod extending substantially along said handle member, and torque indicating means attached to said handle member near the other end-thereof for connection to the other extremity of said elongated rod which' indicating means.

KENNETH R. LARSON. 

